What is a ‘Minsky Moment’

(emphasis is mine)

Minsky Moment refers to a period of time when a market fails or falls into crisis after an extended bullish period with highly inflated market speculation and unsustainable growth. A Minsky Moment is based on the idea that periods of bullish speculation, if they last long enough, will eventually lead to crisis and the longer speculation occurs the worse the crisis will be. This crisis is named after Hyman Minsky, an economist and professor famous for arguing the inherent instability of markets, especially bull markets. He felt that long bull markets only ended in large collapses.